MID-7484: transport config refresh removes only old config transports

Dynamic instance registration should be driven mainly by sysconfig,
but sometimes explicit registrations are used (e.g. dummy).
Transport service now remembers what transports are registered based on
the sysconfig and removes only these when the sysconfig is changed.

model/notifications-impl/src/main/java/com/evolveum/midpoint/transport/impl/TransportServiceImpl.java

@@ -6,6 +6,8 @@
  */
 package com.evolveum.midpoint.transport.impl;
 
+import java.util.ArrayList;
+import java.util.List;
 import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;
 import javax.annotation.PostConstruct;
@@ -46,6 +48,12 @@ public class TransportServiceImpl implements TransportService {
 
     private final Map<String, Transport<?>> transports = new ConcurrentHashMap<>();
 
+    /**
+     * This holds the names of the transports configured from system config object.
+     * When new config is read we don't want to remove other transports registered explicitly (e.g. tests).
+     */
+    private final List<String> transportsFromSysConfig = new ArrayList<>();
+
     // injected fields for TransportSupport
     @Autowired private ApplicationContext applicationContext;
     @Autowired private PrismContext prismContext;
@@ -92,6 +100,8 @@ public ApplicationContext applicationContext() {
                 return applicationContext;
             }
         };
+
+        registerLegacyTransports();
     }
 
     /**
@@ -100,8 +110,7 @@ public ApplicationContext applicationContext() {
      */
     @EventListener
     public void refreshTransportConfiguration(SystemConfigurationChangeEvent event) {
-        transports.clear();
-        registerLegacyTransports();
+        clearPreviousConfiguration();
         createTransports(event.getSystemConfiguration());
     }
 
@@ -129,7 +138,6 @@ public void registerTransport(@NotNull Transport<?> transport) {
 
     // TODO should be internal and go away eventually
     // accepts name:subname (e.g. dummy:accounts) - a primitive form of passing parameters (will be enhanced/replaced in the future)
-
     @Override
     public Transport<?> getTransport(String name) {
         Transport<?> transport = transports.get(name);
@@ -155,7 +163,14 @@ private void createTransports(SystemConfigurationType systemConfiguration) {
             createCustomTransport(customConfig);
         }
 
-        // TODO
+        // TODO other types
+    }
+
+    private void clearPreviousConfiguration() {
+        for (String transport : transportsFromSysConfig) {
+            transports.remove(transport);
+        }
+        transportsFromSysConfig.clear();
     }
 
     private void createCustomTransport(CustomTransportConfigurationType customConfig) {